AT&T was the sole telco for 70 years until its court-ordered breakup in 1984 – a “natural monopoly” built out of ownership of the infrastructure.

But even without a physical network, Hollywood has been the prime channel to the movie market since the 1920s and the big TV networks still dominate television.

Now each internet sector is dominated by one or two firms.

“The internet has long been held up as a model for what the free market is supposed to look like — competition in its purest form,” Wu writes in a column in WSJ.

“So why does it look increasingly like a Monopoly board? Most of the major sectors today are controlled by one dominant company or an oligopoly. Google ‘owns’ search; Facebook, social networking; eBay rules auctions; Apple dominates online content delivery; Amazon, retail; and so on.”

He thinks consumers tacitly allow this because of their preference for convenience.

I’d argue that in digital markets there’s no room for second or third. If there’s one excellent search engine or online store, who needs another?

In the cases of social media, the network effect really matters. Facebook and Twitter are de facto – yes, “natural” – monopolies.

Wu, who coined the phrase “network neutrality,” believes web monopolies are likely though not necessarily inevitable. Much depends on the attitude of users, governments and regulators.